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U2 Programmer

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  • U2 Programmer

    PBP3 and a U2 usb programmer. Red light blinks on programmer while programming but the code isn't in the chip. This is a new setup ...... what did I miss?


  • #2
    U2 Programmer Update

    Hi, After reinstalling everything again..... it's a bit closer I think. When you program a chip the red light blinks once and the (lost communication with device) msg is displayed.

    Hope this is a simple fix.



    • #3
      The "Lost Communications" error usually means that too much current is being drawn from Pin-4 of the programmers 10-pin header.

      Pin-4 is the switched VDD output which is only meant to power the ZIF adapters.
      It cannot supply enough current to power an entire PC board, especially when there are large caps on the power rails.
      The in-rush current to charge the caps causes the voltage to drop far enough to reset the processor in the U2, and you get the "Lost Communication" error.

      If you have Pin-4 connected to your circuit, disconnect it.
      If you need to power your circuit from the programmer, use Pin-1 (fixed +5V direct from the USB bus).

      If you are powering your circuit externally, definitely DO NOT connect Pin-4 or Pin-1.

      The reason for the low current limit on Pin-4 is for when someone puts a chip in the ZIF socket the wrong way.
      It protects both the chip and the programmer.
      In which case, you may also get the "Lost Communications" error.
      PBP3 Manual : Microchip Datasheets - 10F, 12F, 16F, 18F
      Never download a PIC datasheet from anywhere but


      • #4

        Thanks for your help ..... it is working fine now.